Artificial leg.



No. 762,031. PATENTED JUNE 7, 1904. W. ENGELS. v ARTIFICIAL LEG.

APPLICATION rmm mm: 25, 1902. no IODEL. 2 SHEETS-SHEET 1.

No. 762,031. PATENTED JUNE '7, 1904.

w. ENGELS. ARTIFICIAL LEG.

APPLICATION FILED JUNE 25, 1902.

wane rz y Jazz-76 Patented June '7, 1904.

PATENT OFFICE.

WALTER ENGELS, OF HAMBURG, GERMANY ARTIFICIAL LEG.

SPECIFICATION forming part of Letters Patent No. 762,031, dated June '7,1904:-

Applieation filed June 25, 1902.

To all whom it may concern.-

Be it known that I, WALTER ENGELS, acitizen of the Kingdom of Prussia,and a resident of Hamburg, in the German Empire, have invented a certainnew and useful Improvement in Artificial Limbs, of which the followingis a specification.

My invention relates to artificial limbs; and its object is to providesuitable means whereby the movably-connected or jointed members of suchlimbs, as artificial legs or arms, may be rendered capable, even when ina bent position, of supporting the weight of the body thrown thereon orpart of such weight.

To this end my invention consists in the improved construction orcombination of parts whereby upon one of two jointed artificial limbs ormembers becoming depressed by the weight thrown thereon the verticalmovement of the upper limb or member upon the lower through a slot at ornear the knee-joint acts to operate a brake or clamping device locatedWithin the other limb or member, thereby locking both limbs or membersrela- J tively to each other in whatever position they may at the timebe occupying relatively to each other, the said limbs or members thenremaining thus rigidly locked until relieved from the weight, whereuponthey will then be free to move in their joint again. In the preferredform of my invention the means for thus operating the said brake orclamping device consists of a rod connected with its one end to the saidbrake or clamping device and with its other end to an axis verticallymovable in a slot at the joint of both limbs or members, so that thesaid brake or clamping device may be operated from the said other limbor member through the latter becoming depressed by the Weight of thebody thrown thereon. Any tendency of the said members while locked inthe bent position to bendstill further under the action of the weightresting thereon will, according to a preferred form of my invention,cause a lever to press one of the brake parts so much more firmlyagainst the other part or parts, thereby increasing the efficiency ofthe locking action.

According to one form of my invention the brake device located in thelower limb or memserial No. 113,167. (No model.)

ber of an artificial leg, for instance, upon being operated as abovereferred to will act upon a strap or band which passes from the uppermember into and through the lower member, and by clamping the said strapor band between a brake-block and an abutment surface will lock bothlimbs or members, thus rendering them rigid in their common joint.

In the drawings illustrating my invention as applied to an artificialleg, Figure 1 is a vertical section on the line m m, Fig. 3, of anartificial leg embodying my invention with parts broken away. Fig. 2 isan elevation, partly in vertical section, of a detail with parts brokenaway. Fig. 3 is a vertical section on the line fl/ 1 Fi 1, with partsbroken away. Fig. 4 is a horizontal section on the line 2 2', Fig. 1.

a is the upper member; 5, the lower member. The brace-rod c of the uppermember is provided at its lower or joint end with a transverse axis f,capable both of a rotary movement and of a sliding movement within theinclined slot 0 of the brace-rod (Z of the lower member 6. Pivoted onthe said axis, in the center thereof, is a depending arm having a plateIt rigidly secured to its lower end. If

weight is thrown upon the upper member (1/,

the axis f will slide downward in the slot 0, whereby also g and It willbe pressed downward. As shown in the drawings, a bridge 1), obliquelyascending from front to back, is provided within the lower member 6below plate It, the said bridge widening out below plate 71, so as toform an equally large bearing-surface 71 parallel to plate It. Inbrackets -m, mounted on the bridge 1), is fulcrumcd the lever s, thesaid lever being movably connected at its one end to the arm 0 above theplate 72., while its other free end is provided with a roller 0. Otherbrackets Z, provided at a point nearer the other end of the bridge p,have a roller 1i. journaled therein.

A strap 71:, secured near the knee. (1 of the upper member (0, passesthence down through a slot in front of the lower member 6 and below therollers 0 and 02. between it and p, finally emerging at the rear of thelower member b and terminating at the back of the upper member a, whereit is fastened at a". When no weight rests on the limb, the said strapis runs freely through the lower member Z) without impeding itsmovements. As soon, however, as the axis f, together with the arm 0 andplate lt, becomes depressed under the action of a weight brought to bearupon them the strap Z: becomes firmly clamped between it and 2'. If,owing to an increase of the weight, the knee-joint bonds, the strap Z7,hitherto lightly clamped between /L and t', becomes stretched in front,thus tending to diminish the acuteness of the angle at 0, and therebyraising the left arm of the lever shown in the drawings. The plate itthus being more firmly depressed. by the right arm of the lever .9 shownin the drawings the strap Z2 becomes all the more firmly clamped thegreater the strain in bending. Thus the arm g, forming a continuation ofthe bracerod 0 of the upper member a, has become the point of supportfor the said upper member, whereas the fulcrum-point of the knee-jointnow lies approximately at q. Thus an imaginaryone-armed lever hasformed, as it were, having its point of support near 9 and itsbearing-point vertically beneath the center of gravity of the weightedbodythat is to say, behind the leg. The axis f near the fulcrumpoint ofthis lever is very forcibly depressed. Therefore as soon as the strapbegins to be clamped under the action of the weight every attempt atcontinuing to bend the leg can only result in the latter becoming morefirmly locked. On the weight being removed the lower member 5, by reasonof its own gravity, depresses the brace-rod (Z, together with the slot0. In other words, f, g, and h are raised, the strap l. is released, andthe joint will then again be free to move.

Although I have hereinbefore and in the drawings described and shown myinvention as applied to an artificial leg and knee-joint, it is by nomeans restricted to this mode of application, but may be similarlyemployed in other limbs and joints. Neither do I limit myself to theexact details of construction shown.

Having now described my invention, what I claim as new, and desire tosecure by Letters Patent, is-

1. In an artificial limb the combination, with an upper member and aconnected lower member both capable of angular and limited verticalmovement relatively to each other, of flexible supporting and guidingmeans,such as a strap, extending from the upper member through the lowermember below the center of angular movement of the latter, a clampingdevice arranged within the lower member in the line of movement of thesaid supporting and guiding means and operatively connected with theupper member, and a movable conneetion in a slot at the knee-jointpivot, for moving the said clamping device into engagement with the saidsupporting and guiding means by a vertical movement of one member uponthe other, substantially as and for the purpose described.

2. In an artifical limb embodying two mov ably-connected members and astrap extending from the one member through the other member along abearing-surface within the latter, the combination, with the said strapand bearing-surface, of a lever fulcrumed within the last-named member,a clamping-plate connected with the one arm of the said lever and meansfor operating the said lever and clamping-plate from without to clampthe said strap against the said bearing-surface, substantially asdescribed.

3. In an artificial limb the combination, with an upper member and aconnected lower member, both capable of angular and limitedverticalmovement relatively to each other, of a flexible supporting and guidingmeans, such as a strap, extending from the upper member through thelower member, the latter being suspended from, and capable of a slidingmovement along the said supporting and guiding means, a bearing-surfaceimmediately below the latter, a clamping-plate immediately above thesame, connections between the said clamping-plate and the upper member,a lever fulcrumed within the lower member, with its one arm movablyconnected above the clamping-plate audits other arm bearing on the saidsupporting and guiding means with a roller provided thereon,substantially as and for the purpose described.

4. In an artificial limb having an upper member and a connected lowermember capable of angular and limited vertical movement relatively toeach other, astrap secured with its one end to the front side of theupper member, passing thence downward into and through the lower member,emerging from the latter in the rear and having its other end secured tothe rear side of the upper member, a clamping mechanism operated by avertical movement of the upper member to clamp the said strap against abearing-surface within the lower member, a lever having one armoperatively connected with the said clamping mechanism and the other armexposed to the strain of an angular portion of the said strap betweenthe point of engagement of the said clamping device and the front end ofthe said strap, substantially as and for the purpose described.

5. In an artificial limb the combination,with the upper and lowermembers, of the strap 70, the bridge 7), bearing-surface 2', brackets Zwith roller a, brackets m with lever .9 having roller 0, clamping plate/1., arm g, axis f, brace-rods (Z with slot 0, brace-rod 0.

' WV ALTER ENGELS.

itnesses:

E. H. L. MUMMENHOFF, OTTO WALTER HELLMRIOH.

